复合型核-壳结构正极材料LiNixCoyMn(1-x-y)O2的设计合成与储锂性能的基础研究

项目名称： 复合型核-壳结构正极材料LiNixCoyMn(1-x-y)O2的设计合成与储锂性能的基础研究

项目编号： No.51502350

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 一般工业技术

项目作者： 童汇

作者单位： 中南大学

项目金额： 21万元

中文摘要： 三元材料LiNixCoyMn(1-x-y)O2具有能量密度高和成本相对较低等优势，是极具有发展潜力的正极材料之一。然而，该材料的循环性能和倍率性能较差，制约了其在动力电池中的应用。本项目拟设计合成一种复合型的核-壳结构三元材料，来提高材料的电化学性能。通过设计具有浓度梯度的核和具有微孔结构的壳相结合的方式，缩短了锂离子和电子的扩散路径，提高了材料的循环稳定性；研究材料的制备过程，明确了材料微观结构调控的机理；通过V2O5纳米颗粒的包覆，增强了锂离子的传导率；通过石墨烯的包覆，形成三维导电网络结构，提高材料的电子导电率；双包覆的结构设计有效的抑制了电解液对金属化合物的溶解。通过研究材料的循环稳定性以及倍率充放电过程中容量的衰减机理，得到了材料微观结构与电化学性能之间的构效关系，为制备出性能优异的动力锂离子电池正极材料提供了理论指导。

中文关键词： 锂离子电池；正极材料；结构调控；电化学性能

英文摘要： LiNixCoyMn(1-x-y)O2 has been considered as a very promising cathode material due to its high energy density and relatively low cost. However, it has shown poor cycling and rate performance, restricting its application in the field of power batteries. In this study, we try to design and synthesize a complex core-shell structured LiNixCoyMn(1-x-y)O2 to improve its electrochemical performance. The diffusion path of lithium ions and electrons is shortened, and the cycling stability is improved in the material consisting of concentration-gradient solid core and porous shell; The microstructure control mechanism is clarified in the study of preparation process; Lithium ionic conductivity is improved by V2O5 nanoparticles coating; Three-dimensional conducting networks are formed by reduced graphene oxide coating, resulting in the improvement of electronic conductivity. Meanwhile, the dissolution of metal compound in electrolyte is inhibited by the double coating layers. The relationship of microstructure and electrochemical performance is clarified in the study of the cycling stability and the mechanism of capacity fade of the rate performance, which could provide theoretic guide for the synthesis of lithium ion power battery cathode materials with outstanding performance.

英文关键词： Lithium ion battery;Cathode material;Structure control;Electrochemical performance